Evaporation-Induced Transformations in Volatile Chemical Product-Derived Secondary Organic Aerosols: Browning Effects and Alterations in Oxidative Reactivity

Environmental Science & Technology, Год журнала: 2024, Номер 58(25), С. 11105 - 11117

Опубликована: Июнь 12, 2024

Volatile chemical products (VCPs) are increasingly recognized as significant sources of volatile organic compounds (VOCs) in urban atmospheres, potentially serving key precursors for secondary aerosol (SOA) formation. This study investigates the formation and physicochemical transformations VCP-derived SOA, produced through ozonolysis VOCs evaporated from a representative room deodorant air freshener, focusing on effects evaporation its molecular composition, light absorption properties, reactive oxygen species (ROS) generation. Following evaporation, solutes become concentrated, accelerating reactions within matrix that lead to 42% reduction peroxide content noticeable browning SOA. process occurs most effectively at moderate relative humidity (∼40%), reaching maximum solute concentration before solidification. Molecular characterization reveals evaporating SOA produces highly conjugated nitrogen-containing interactions between existing or transformed carbonyl reduced nitrogen species, likely acting chromophores responsible observed brownish coloration. Additionally, reactivity was elucidated heterogeneous oxidation sulfur dioxide (SO

Язык: Английский

Biomass-burning organic aerosols as a pool of atmospheric reactive triplets to drive multiphase sulfate formation

Proceedings of the National Academy of Sciences, Год журнала: 2024, Номер 121(51)

Опубликована: Дек. 13, 2024

Biomass-burning organic aerosol(s) (BBOA) are rich in brown carbon, which significantly absorbs solar irradiation and potentially accelerates global warming. Despite its importance, the multiphase photochemistry of BBOA after light absorption remains poorly understood due to challenges determining oxidant concentrations reaction kinetics within aerosol particles. In this study, we explored photochemical reactivity particles S(IV) oxidation sulfate. We found that sulfate formation under is predominantly driven by photosensitization involving triplet excited states ( 3 * ) instead iron, nitrate, photochemistry. Rates three orders magnitude higher than those observed bulk solution, primarily fast interfacial reactions. Our results highlight chemistry can greatly contribute sulfate, as an example secondary pollutants. Photosensitization will likely become increasingly crucial intensified wildfires.

Язык: Английский